Webbed open-end box wrench



Aug. 16, 1955 R. N. JOHNSON 2,715,347

WEBBED OPEN-END BOX WRENCH Filed Dec. 2, 1952 INVENTOR RICHARD N. JOHNSON @Zmz? ATTORNEYS United States Patent WEBBED OPEN-END BOX WRENCH Richard N. Johnson, Los Angeles, Calif., assignor to Tubing Appliance Company, Inc., a corporation of California Application December 2, 1952, Serial No. 323,589

3 Claims. (Cl. 81-121) This invention consists in new and useful improvements in an open-end box wrench and more particularly a box wrench head provided with a tension Web designed to resist the separating forces when torsional moment is applied.

Wrenches of this type are generally used in confined areas where it is often necessary to apply a considerable force in tightening or releasing a nut, for example at an intermediate point in a piping system. With the standard open-end box wrench or crowfoot wrench now on the market, the wrench head is extremely weak and will spread under very low pressures, thus deforming the gripping portion of the wrench head and either rendering it useless or greatly decreasing its efficiency. Furthermore, with the conventional open-end box wrench, particularly when used in locations where access is difficult, extreme care and accuracy is required in order to fit the wrench head onto the nut and also to prevent the wrench head from sliding past its gripping engagement with the nut.

It is the primary object of the present invention to provide an open-end box wrench having a crescent-shaped side wall, said side wall being surmounted by a slotted end wall which provides a continuous tension web and which, in addition to resisting forces tending to spread the open end of the wrench upon the application of torque, serves the purpose of preventing the wrench head from slipping past a nut being rotated.

With the above and other objects in view, which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Fig. 1 is a top plan view of a wrench embodying the novel features of the invention, manufactured by the hot punch method;

Fig. 2 is a longitudinal sectional view of the wrench head shown in Fig. 1;

Fig. 3 is a top plan view of a slightly difierent form of the invention, manufactured by the extrusion or forged method; and

Fig. 4 is a longitudinal sectional view of the wrench head shown in Fig. 3.

In the drawings, the numeral 5 designates the box portion of a bifurcated wrench head which is preferably formed as an integral structure having a depending annular wall 6, separated at its forward end by a vertical throat 7. A substantially cylindrical cavity 8 is formed within the wall 6, having its entrance opening at one end face of the wrench head, to form a nut-receiving socket, the inner wall of said cavity being provided with a series of peripherally spaced teeth or nut-engaging surfaces 9. These surfaces may vary in number to meet different requirements, but in the form of the invention here illustrated, the cavity 8 is designed as a twelve point socket.

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As will be seen from Fig. 1, the vertical axis A of the cavity 8 is offset forwardly of the corresponding axis B of the head proper 5, so that in horizontal section, the annular wall 6 is substantially crescent-shaped, and tapers toward the opposed vertical edges of the throat 7. Thus, the wall 6 is gradually thickened toward the inner side of the head to reinforce the box structure 5, without materially increasing its bulk or its outside dimensions.

On that end face of the wrench head opposite the entrance opening of cavity 8, there is provided a tension web 10, the central portion of which is cut out as at 11, to form a longitudinally directed slot, extending inwardly from a point adjacent the throat 7 and terminating in an arcuate closed inner end 11a, the axis of curvature of which is concentric with the axis of the cavity 8. The web 10 as clearly shown in the drawings, is arranged to over-lie a substantial portion of the cavity 8, the size of the slot 11 and the radius of its closed end 11a, being determined by the size of the nut and tubing or rod with which the wrench is to be used. In other words, the web 10 must be of a suificient area to act both as a torque resisting member and as a positioning abutment for a nut located in the recess 8, and the slot 11 must have suflicient transverse dimension to receive a tube or rod which extends through the nut being worked upon.

The side of the Wrench head, opposite the throat 7 is longitudinally extended to form a handle-receiving shank 12, having a squared transverse opening 13 for receiving the squared pivoted end of a handle extension 14. It will be understood that instead of the arrangement just referred to, the shank 12 itself, may be extended to form a handle which is integral with the head 5. However, for purposes of facilitating access to difficult locations and affording increased leverage, the arrangement for accommodating the pivoted handle extension 14 is preferred.

In the form of the invention illustrated in Figures 1 and 2, the wrench head is formed by the hot punch method and to facilitate this operation an annular recess 15 is provided in the inner surface of wall 6 at the upper extremity of the cavity 8. This annular recess is formed immediately below the over-hanging web 10 and extends entirely around the inner wall of the cavity to permit the forming of the teeth 9 by the use of a properly shaped punch.

In the form of the invention illustrated in Figures 3 and 4, the wrench head is formed by the extrusion or forged method and the recess 15 is omitted. In forming the wrench by this method, the cavity in the die is approximately the same shape as the wrench head is on the outside perimeter. A red hot slug of metal is placed in this cavity with no preforming of the slug. The red hot slug is then engaged by a twelve point punch which descends in the cavity and presses into the slug, forcing the walls up around the twelve point punch. The dies are generally split for ejection of the work.

In both forms of the invention the essential feature lies in the formation of an integral head with an open work-receiving cavity 8 having a series of teeth or workengaging surfaces 9 around its inner periphery and an inwardly over-hanging tension web 10 which extends entirely around the bounding walls 6 of the cavity and is provided with a central slot 11 to accommodate the tube or rod with which the nut is engaged.

It will be apparent that this web structure greatly strengthens the wrench head without adding bulk to the outside diameter of the wrench and resists the separating forces when torsional moment is applied. As an added feature, the web 10 serves as a locating abutment for the top of the nut and prevents the wrench head from slipping beyond the nut.

A wrench of this type may readily be applied to a nut From the foregoing it is believed that my invention may be readily understood by those skilled in the art, without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the scope of the invention as set forth in the following claims.

I claim:

1. A box wrench, comprising: a bifurcated head having exterior Wall means defining a substantially cylindrical outer contour, said head having inner wall means defining a nut-receiving cavity formed jointly by the, bifurcations of said head and accessible from one face of the head on an axis parallel to a longitudinal axis of said cylindrical outer contour of said head; the opposed extremities of said bifurcation defining an end throat communicating with said cavity, the access axis of said cavity being ofiset toward said end throat with respect to said axis of the head, whereby the wall means defining said cavity is substantially crescent shaped intransverse section, and provides a thickened reinforcing portion at that side of the head opposite said throat; a flange projecting radially inwardly from the inner surfaces of the cavity at that face of the head opposite said one face; a free inner edge of said flange defining a central slot 4 which extends from the end throat toward said thickened portion and terminates in an arcuate closed end having its axis of curvature concentric with the axis of the cavity; and an operating shank carried by said head adjacent said thickened portion.

2. A box wrench as claimed in claim 1, wherein the opposed extremities of said bifurcations defining said throat, and those portions of said flange inner edge located adjacent said throat, are flared outwardly to facili tate reception of a tube or rod.

3. A box wrench, comprising: a head element having end and side wall means defining a substantially cylindrical outer contour and inner wall means defining a workpiece-receiving cavity opening inwardly from one end face of said head element and having its workpieceengaging axis oifset from a longitudinal axis of said cylindrical outer contour of said head element, whereby the wall means defining said cavity is substantially crescent shaped in transverse section and provides a thickened reinforcing portion at one side of said head element; the end and side wall means of said head element having merging slots communicating with said cavity; the slot of said end wall means extending toward said one side of said head and beyond the axis of said cavity; the imperforate portion of said end wall means forming a tension web overlying said cavity and further reinforcing the side wall means thereof; and means for attaching 7 an operating shank to said head element.

References Cited in the file of this patent UNITED STATES PATENTS 1,224,875 Zarth May 1, 1917 2,358,555 Blanchard Sept. 19, 1944 2,578,687 Fish Dec. 18, 1951 

